Power driven toothbrush



March 3, 1942. J CAVANAGH 2,275,247

POWER DRIVEN TOOTHBRUSH Filed Feb. 6, 1939 r 62 101 Framing/t w2fl4/ K I d A TORNEY$ Patented Mar. 3,

UNITED STATES PATENT orrics I I A. I v POWER nitl vi lz r omntlsfl 4 1011!! F. Cavanagh, Jackson Hdhil, N," Y. Application February 6, 193, sell! No. 254,803

9 Claims. (CI- 1523) brush and other attachments may be interchanged.

Science discloses that teeth are connected to the jaw on the outside, with a primary cuticle, which is an epithelial attachment of the gum to.

the enamel of the tooth. This primary cuticle is commonly known as the gum margin. If the gums were caused to recede either by improper brushing of the teeth or by other causes, such recession may and usually does result in the exposure of the roots of the teeth. When exposed it is almost impossible to restore this epithelial contact again. The tissue sooner or later becomes inflamed and/or diseased, causing it to break down and eventually lead to permanent destruction of the alveolar bone that holds the teeth solidly. If the gums are not properly treated, this condition may soon develop into a serious case of pyorrhea and the eventual loss of teeth. As a part of the treatment for pyorrhea, or as a treatment to increase the local resistance against the development of pyorrhea, it is important that the gums be periodically brushmassaged to stimulate the blood supply.

- while most people understand that to properly brush teeth and massage gums the brush should be moved in one-way strokes across the gums and toward the'teeth, very few people do so. To move the ordinary tooth brush in manner is tiring and requires considerable patience. For this reason, but few people massage their gums and clean their teeth in the most desirable and effective manner.

By the present invention I provide a power driven tooth brush which not only enables the user to easily and thoroughly clean his teeth but also to properly massage the gums without danger of iniuring the gums or other portions of the mouth. More particularly, the power driven tooth brush of my invention comprises a motorcontained handle having coupling means which provide for either a friotion or positive driving connection for tooth brush attachments or other detachable devices such, for example, as shavers, buil'ers or the like. The tooth brush attachment is provided with means for releasably supporting interchangeable brush elements in friction driving relation with the shaft of the attachment. prevents the user from pressing a rotating brush with injurious force against the gums or other "portions of the mouth. To shield the inside of the mouth from the rotating brush, a guard is provided for covering one side of the brush. This guard is pivotally supported so that it may be readily swung out of shielding position for cleaning purposes or for the interchanging of brush elements.

Another feature of my invention is the provision of a control device within the handle for controlling operation of the power driven brush or other attachment. This device includes an actuating stem extended outwardly of the handle in a convenient location for actuation by either the thumb or forefinger of the hand 81199 118 the handle. The device is so constructed that when the stem is moved a predetermined amount relative to the handle, the motor is caused to drive the brush in one direction, and upon another or further movement of the stem the motor is caused to drive the brush in the reverse direction. This reversing feature enables the user to shift the brush from the upper to the lower teeth and to the back side thereof and still be able to direct the rotation of the brush across the gums toward and over the teeth.

One of the objects of the present invention, therefore, is to provide a power driventooth brush capable of use by members of a family for cleaning teeth and n: w: gums without danger of injuring the gums or other portions of the mouth.

Another object of the invention is to provide .a power driven tooth brush having a provision for.releasab1y connecting brush elements thereto in a friction driving relationwith the source of "power This frictional drive is important since it 7 Another object of the invention is to provide apowerdriventooth brushhavingaguardelement which is easily manipulated to permit cleaning and the interchanging of brush elements without the necessity of detaching the same.

Another object of the invention is to provide a power driven tooth brush having means whereby the movement or direction of movement of the brush is easily and readily controlled by the user.

Another object of the invention is to provide a power driven tooth brush or the like having means whereby tooth brush attachments or other devices may be interchanged and secured thereto with either a friction or' positive driving connection.

Other objects and advantages of the invention will become apparent upon consideration of the following detailed description and the appended claims when read in connection with the ac ll companying in which:

Figure 1 is an elevational viewof a form of a. powerdriven tooth brush made in accordance with this invention, parts being broken away to show details thereof;

Figure 2 is a sectional view takenalong line. 2-2 of Figure l; v

Figure 3 is, an enlarged sectional view taken along line 3-3 of Figure 1;

Figure 4 is an enlarged elevational view of the end portion of a tooth brush attachment;

Figure 5 is an enlarged elevational view of the head end of the handle showing a portion of the coupling means for securing tooth brush and other attachments thereto;

Figure 6 is an enlarged eievational view partly in section taken along line 6-6 of Figure 1, with a diagrammatic showing of the motor and its electrical connections;

Figure 7 shows a mcdified form of brush element and releasable connection therefor; and

Figure 8 is an elevational view showing a shaver attachment substituted for the tooth brush attachment.

That form of the power driven tooth brush illustrated in Figures 1 to 6 of the drawing comprises a motor contained handle ID, a brush attachment l2 and a coupling device l4 for securing the attachment to the handle. The attachment l2 comprises an elongated housing ii in which a shaft I8 is suitably journaled. The outer end of the shaft I8 is provided with a slot 28 in which a resilient element 22 is mounted, the resilient element being shaped to protrude from the slot as at 24 for releasably securing brush elements 26 to the shaft l8.

Each brush element 26 includes a sleeve 28 upon which the bristles 30 are suitably mounted. The sleeve 28 is provided with an inner annular recess or groove 32 adapted to receive the protruded portion 24 of the resilient element 22 when the brush is slid onto the end of the shaft I8. The slot 20 extends from a point adjacent the end of the shaft l8 leaving a portion 34 to substantially close the outer end of the sleeve. The sleeve 28, however, maybe closed at the outer end as illustrated in Figure '7, in which case the end of the shaft would be shortened so as to terminate within the sleeve.

The provision of the annular groove 32 not only provides for releasably securing the brush upon the shaft I8 regardless of the position of the brush element when slidonto the shaft, but also provides for a frictional driving connection between the brush and shaft so that should the brush be held against the gums or teeth with too great a force, the brush will slip relative to the shaft and thereby prevent the user from injuring himself. The bristles 30, which may be of synthetic or natural material, are preferably of a non-cutting character so that all danger of cutting or wearing away of the gum tissue or enamel when driven at full speed is eliminated.

Referring to Figure '7 of the drawing, a modified form of brush and releasable connectingmeans therefor is illustrated. The shaft |8a is formed into a pair of spring-like prongs 36 and 31, each of which is provided with a laterally extended neb 38 adapted to be received in the groove 32a of the brush element 26a. When the brush 5': slid onto the end of the shaft, the prongs 36, 31 give inwardly until they reach the groove 32a whereupon the nebs 38 are received by the groove to releasably hold the brush element in operative position adjacent the collar 38. Since the end of the shaft l8a does not provide a closure for the outer end of the sleeve 284, the sleeve may be formed with a closed end as indicated at 40.

To provide a driving connection between the motor shaft 4| and the shaft I8 I provide a tubular shaft 42 adapted to receive the inner end of the shaft II which may be forked as indicated at 48 and/or provided with a resilient friction engaging element 44 similar to the-resilient element 22. The resilient element 44 also protrudes from the shaft I8 so that when received in the tubular shaft 42 it will bear in friction driving engagement with the inner surface thereof. The coupling device H, which is fully described hereinafter, may be constructed for detachably securing the housing I8 in two different positions so that the shaft l8 maybe received in the tubular shaft 42 for either friction driving engagement with the inner surface thereof or in positive driving connection with a coupling pin 45 extended transversely of the tubular shaft 42. A friction drive may thus be established within the handle, should the handle be used with attachments having the driven element thereof positively connected to the shaft l8; or the inner friction drive may be established as an additional safety feature to further insure a friction drive for brush elements frictionally connected to the shaft I 8, it being recognized that foreign substance or dentifrice may possibly get into the slot 20 or sleeve 26 and substantially increase the gripping action of the friction drive between the brush and shaft. Then again, the friction drive may be preferable to a positive drive for attachments other than tooth brushes.

The tubular shaft 42 is operatively connec ed to the motor shaft 4| by an interconnecting disk 46 formed of insulating material. Since the handle I0 is made of synthetic or other material having insulating properties, the provision of the disk 46 effectively insulates the coupling means and attachments secured thereto from the motor and its electrical connections.

The housing l6 of the brush attachment I2 is provided with an enlarged end 48 adapted to be received and detachably secured in a selected position relative to the handle II by the coupling device l4. The head 50 of the handle is provided with a neck portion 52 upon which the coupling device I4 is mounted. The coupling device includes a sleeve 53 mounted on and secured to the neck portion 52 by a set screw 54. The sleeve 53 is provided with opposed clamping elements 55, 56 and 51, 58 spaced thereabout as illustrated in Figures 1, 3 and 5. These clamping elements are connected to the sleeve portion by a narrow strip 60 so that each is provided with a certain degree of resiliency. The clamping elements 55 and 56 each have an inwardly extended bead 62 adjacent the outer edge thereof for entrance into either of the grooves 64 or 65 on the enlarged portion 48 of the housing l6. The clamping elements 51 and 58 are not provided with beads as in the case of elements 55 and 56, but are sprung slightly inwardly so as to releasably .grip the housing l6 when the housing is inserted into the coupling device. A collar 66 is rotatably mounted on the clamping elements 55 to 58, the collar being retained thereon by means of a set screw 61 slidably receivable in grooves 68. The collar 66 is provided with opposed cam surfaces 68 and 68 which, when the receding portions thereof are in position overlying the clamping elements 55 and 56, permit the housing l6 to be inserted or withdrawn at will from the coupling device l4, the clamping elements 55 and 56 being normally sprung slightly outwardly.

Figure '1.

'To lock the housing within the coupling, the collar 88 is rotated to bring the raised portions of the cam surfaces 88 and 88 to bear upon the clamping elements 85 and 88, causing the beads 62 to enter the selected groove on the enlarged portion of the housing i8. To release the housing the collar 88 must be rotated to relieve the provided with a detent I8 receivable in recesses 18 formed in the sides of the housing l8. To insure the guard from being forced against the brush 26, the guard is provided with an abutment 88 adapted to engage the housing i8 as shown in The guard'when desired may be swung backwards upon the housing to facilitate the cleaning of the brush and guard and/or the interchanging of brush elements.

Many people, especially when first using power driven tooth brushes, may be nervous and in order to prevent a nervous person from inadvertently injuring himself by the rotary action of the brush, I have provided the power driven device with a control switch which, when released, will stop the motor. This control switch as shown in Figures 1 and 6, includes two series of stationary contacts mounted within the handle ill'adjacent a plate 82 slidably retained in a recess 84 formed in the head portion 58. The switch plate 82 is provided with a stem 85 for extension outwardly of the handle ill, the plate being biased to its outer or neutral position by a spring 88. To seal the handle ill at the stem 85 a piece of flexible material is secured to the handle at points adjacent the stem to provide a flexible cover 81 for the outer end of the stem. Superimposed on the illustration in Figure 6 is a wiring diagram indicating the connections and relative positions of the stationary contacts, the plate 82 being provided with a pair of metallic elements 88 and 88 adapted to bridge certain of the stationary contacts as the stem 85 is actuated. The stationary contacts of the switch are arranged to connect the rotor 88 and field coil 8i in series, the connections to the field coil being reversible by movement of the plate 82. When the stem 85 is first moved the elements 88 and 88 bridge the first and second pairs of the two series of stationary contacts whereby the rotor and coil are energized to drive the brush in one direction. Upon further movement of the stem 85 the elements 88 and 88 disengage the first stationary contacts of the two series andv bridge the second and third of the two series of stationary contacts, thereby reversing the field connections and causing the motor to drive the brush in the reverse direction.

.It will thus be apparent that the user may, by pressing the switch stem 85 a slight distance, cause the brush to rotate in one direction and that by pushing the stem 85 still further or to its extreme inward position, the brush 26 is caused to rotate in the reverse direction. Thus, should the user, especially a beginnenbecome nervous and desire to stop the brush, the mere releasing of the stem 85 will permit the spring 81 to move the switch to neutral position and thereby deenergize the motor. It is to be understood that various attachments may be interchanged with the tooth brush attachment either to be driven by positive or friction driving connection. In Figure 8 a shaver attachment 88 is shown secured to the motor contained handle i8. Besides tooth brush and shaver attachments, other attachments such as buffers, nail filing devices and the like may also be provided for interchangeable use.

Although I have shown and described an embodiment of my invention and certain modification thereof, I am fully aware that many other modifications are possible. It is to be understood, therefore, that the forms I have shown and described are illustrative only and are not intended to restrict the scope of the appended claims.

I claim:

I 1. A power driven tooth brush having a shaft adapted to be driven from a source of power, means at one end of said shaft shaped to provide a pair of axially extending prongs, the end of each prong being provided with aportion normally adapted to extend laterally outwardly beyond the periphery of the shaft, and a brush element having an opening through at least the rear end thereof adapted to receive said shaft, the inner surface of said opening being provided with an annular shoulder to engage the laterally extending portions on said prongs, the prongs and said shoulder co-operating to releasably hold said brush element on said shaft and also to provide a sensitive frictional driving engagement therebetween.

2. A power driven tooth brush having a shaft adapted to be driven from a source of power, resilient spreading means provided at the end of said shaft, to releasably hold and to frictionally drive a brush element on said shaft, said resilient spreading means having at least one portion thereof adapted to normally extend beyond the periphery of the shaft and to give inwardly of the periphery when forceably urged inwardly of said shaft and a brush element having an opening through at least the rear end thereof adapted to receive the end of said shaft, the inner surface of said opening being provided with an annular recess having a rear shoulder to receive and releasably retain said resilient spreading means whereby said brush element is held on said shaft, said spreading means being adapted to resiliently bear with sensitive frictional driving contact in said annular recess.

3. A power driven tooth brush having a shaft provided with a recess therein adjacent the end thereof, resilient means mounted within said recess with a portion thereof protruding outwardly of said shaft, and a brush element having a sleeve adapted to receive the end of said shaft, said sleeve being provided with a laterally disposed annular recess in the inner surface thereof to receive the protruding portion of said resilient means for releasably holding said brush element in sensitive friction releasing relation on said shaft.

4. In a power driven tooth brush comprising a housing, a shaft journaled in said housing and a brush carried by said shaft; the combination of a guard for shielding one side of said brush, said guard being provided with a pair of laterally projecting pivot pins, said housing having openings adapted to receive said pins to pivotally support said guard, said guard having an abutment disposed forwardly of said pins to engage said housing to prevent said guard from engaging said brush, and means including coactive gripping portions on said guard and said housing for releasably holding said guard in brush shielding position.

5. In a power driven tooth brush comprising a housing, a shaft journaled in said housing and a brush carried by said shaft; the combination of a guard for shielding one side of said brush, said guard being provided with a pair of arms each having a pin, said housing having openings for' receiving said pins to pivotally support said guard, and means including coactive detent portions on said guard and said housing for releasably holding said guard in brush covering position.

6. In a power driven device comprising a handle, a drive shaft journaled in said handle, and an elongated tooth brush attachment including a housing and a shaft journaled therein; the combination of means for securing said housing to said handle, and'means for telescoping said shafts together to provide a sensitive frictional releasable driving connection wherein one of the shafts is provided with a tubular portion and the other of the shafts is provided with a resilient member disposed against the inner surface of the tubular portion when the housing of said portion is secured to the said handle. I

7. In a power driven device comprising a handle, a source of power associated therewith and a tooth brush attachment to be driven by said source of power; the combination of a drive shaft for said handle operatively connected to said source of power, said drive shaft having means defining a friction engaging surface and a positive interlocking element, and means for detachably securing the attachment to said handle in one position for engagement with the friction engaging surface of said shaft and in a second position for positive driving engagement with said element.

8. In a power driven device comprising a handle,

a source of power associated therewith and a tooth brush attachment having a shaft Journaled therein; the combination of a drive shaft for said handle operativeiy connected to said source of power, said drive shaft having a tubular end portion, a coupling pin extended transversely of said tubular portion at a distance from the end thereof, .said attachment shaft being provided with a forked end and resilient spreading means adjacent said forked end, and means for detachably securing the attachment to said handle in one position wherein said spreading means is adapted to engage said tubular portion to provide a friction driving connection, and in a second position wherein said forked end is adapted to engage said pin for a positive-driving connection.

9. A power driven tooth brush comprising a drive shaft adapted to be driven by a source of power, a brush element, said shaft and said brush element having coactive attachment portions for releasably attaching said brush element to said shaft for frictional driving relation, one of said portions being tubularly shaped to telescopically receive the other of said portions, one of said portions being provided with an annular recess extending laterally into the surface thereof to provide a locking groove, the other of said portions being provided with a recess, and a resilient element mounted in said recess with a portion thereof protruding therefrom to engage said locking groove to provide a releasable locking connection for retention of said brush element on said shaft while at the same time permitting said brush element to slip relative s'aid shaft should said brush element be pressed with an undue force against the teeth, gums or other portions of the mouth.

JOHN F. CAVANAGH. 

